Stabilization of saturated halogenated aliphatic hydrocarbons

ABSTRACT

Method for stabilizing halogenated solvents derived from aliphatic saturated hydrocarbons wherein trioxane is associated with an aliphatic alcohol and/or epoxide liquid at ordinary temperature and this combination is then added to the halogenated solvent.

Unite Patent Qorreia 1 Mar. 27, 1973 [54] STABILIZATION OF SATURATED [56] References Cited LIP I HAT C UNITED STATES PATENTS [75] Inventor: Yves Correia, Saint Auban, France Germany "260/6525 [73] Assigneez Pechiney Saint Gobain, m 3,564,063 2/1971 Cormany ..260/652.5 Seine, France 3,564,061 2/1971 Correla et al ..260I652.5

[22] Filed: Mar. 3, 1971 Primary ExaminerLeon D. Rosdol Assistant Examiner--W.illiam E. Schulz [21] 120539 Attorney-McDougall, Hersch & Scott Related US. Application Data [57] ABSTRACT [63] Continuation-in-part of Ser. No. 753,854, Aug. 20,

l968,abandoned Method for stabilizing halogenated solvents derived from aliphatic saturated hydrocarbons wherein triox- [52] U S Cl 252/165 252/170 260/652 5 ane is associated with an aliphatic alcohol and/or 51 K 6 9/02Cl 1d ePO'xide liquid at ordinary temperature and this com- %58% F geld 17o 17; 260/652 5 bination is then added to the halogenated solvent.

14 Claims, No Drawings STABILIZATION OF SATURATED HALOGENATED ALlPHATlC HYDROCARBONS This is a continuation-in-part of my copending application Ser. No. 753,854, filed on Aug. 20, 1968, and entitled Stabilization of Saturated l-lalogenated Aliphatic Hydrocarbons, now abandoned.

The present invention relates to the stabilization of halogenated aliphatic hydrocarbons saturated in C, to C, and particularly trichloro-l ,1 ,l ethane.

It is very well known that saturated aliphatic hydrocarbons containing certain halogenated substitutes, particularly chlorine, are unstable when placed in contact with metals, such as aluminum or its alloys and magnesium or its alloys, among others. Their insta bility is translated into decomposition of the halogenated hydrocarbon with concomittant formation of halogenated hydracid and coloration of the halogenated hydrocarbon. This constituted a serious inconvenience as to the application of these halogenated hydrocarbons as solvent for grease removal and/or for the cleaning of metal parts or components.

It is also known to use trioxane as a stabilizer. However, at rates of 0.5 to 3 percent by weight, the interval of stabilization time preceding the appearance 'of acid vapors or of a coloration varies from only minutes to 48 hours, which is insufficient for the prolonged use of trichloro-l,1,l ethane in degreasing or cleaning of metal or other objects.

The objective of this invention is to remedy the inconvenience cited above by allowing efficient and prolonged stabilization of the aliphatic halogenated hydrocarbons and thus the carrying out of the grease removal and/or cleaning of metal parts, plastics, textile or other materials, without noticing any degradation of the solvent and of the materials to be treated.

According to the invention, the stabilization of the aliphatic saturated halogenated solvents in C, to C, and particularly of trichloro-l,l,l ethane is accomplished by incorporating therein trioxane associated with an aliphatic alcohol, particularly tertio butanol and/or an epoxide which is liquid at ordinary temperature, particularly butylene oxide.

According to the invention, from 0.001 to 15 percent, preferably from 1 to 5 percent, of trioxane is associated with from 0.1 to 7.5 percent of said aliphatic alcohol and/or from 0.1 to 4 percent of said epoxide. The combination is then incorporated into the halogenated solvent. These percentages are all expressed in weight percentages based on the amount of halogenated saturated aliphatic hydrocarbon.

It has been discovered that the association of the aforementioned organic compounds reinforces the stabilizing effect of trioxane and the stabilization of the saturated halogenated aliphatic hydrocarbons with the aid of the combinations of the aforementioned stabilizers proved particularly advantageous due to the fact that the stabilizing combinations just described have at comparable concentration a clearly higher stabilizing action than the stabilizing action of each of the components taken individually.

It is also possible to associate one or several components having at least one of the following functions, groups or radicals to the trioxane, without going beyond the scope of the invention: thiol, ester such as alkyl orthoformate, alkyl orthoacetate, aliphatic or cyclic acetal, aliphatic organic acid; imino-ether, such as N-alkyl alkoxy-l ethanimine and ketimine such as N- alkyl isopropanimine, an oxygen containing heterocyclic nucleus such as pyrannic heterocycle and/or a nitrogen containing heterocyclic nucleus such as pyrrolic, pyrrolinic and morpholinic heterocycle, alkyl isocyanate, alkyl thiocyanate, alkyl isothiocyanate, alkyl orthocarbonate and carbonate, and specifically an alkyl nitrile such as acetonitrile and nitroalkane such as nitromethane. The aforementioned alkyl groupings have from one to four carbon atoms and the boiling points of the compounds associated with trioxane and used in the stabilization formulas should not differ by more than 50, and preferably by not more than 25 C, from the boiling point of the halogenated saturated aliphatic hydrocarbon in question. The foregoing materials may be associated with the trioxane in an amount within the range of 0.1 to 4 percent by weight and preferably in an amount within the range of 0.3 to 2 percent by weight, based upon the solvent composition.

Among the saturated aliphatic halogenated hydrocarbon derivatives in C, to C, capable of being stabilized by the method of the invention, the following list of compounds may be cited, but this list cannot be considered as limiting: dichloroethanes, trichloroethanes, and particularly trichloro-l, 1,1 ethane, tetrachloroethanes, dichloro-1,2 propane, dichloro-l,2 and -2,3 butanes, tribromo ethanes and dibromo-l ,2-propane.

The invention relates also to the stabilized compounds comprising one or several halogenated saturated aliphatic hydrocarbons in C, to C,, particularly trichloro-l,l ,1 ethane containing from 0.001 to 15 percent by weight of trioxane associated with 0.1 to 7.5 percent by weight of an aliphatic alcohol, particularly tertio butanol, and/or with 0.1 to 4 percent by weight of an expoxide liquid at ordinary temperature, particularly butylene oxide. These compounds may also contain an alkyl nitrile in C, to C,, such as acetonitrile, propionitrile and butyronitrile, in an amount within the range of 0.1 to 4 percent by weight and preferably 0.3 to 2 percent by weight, and/or nitroalkane in C, to C,, such as nitromethane, nitroethane, nitropropane, and nitrobutane, in an amount within the range of 0.1 to 4 percent by weight and preferably 0.3 to 2 percent by weight.

The following examples are merely for the purpose of better pointing out the advantages and different aspects of the invention and should not be considered as restricting its scope:

EXAMPLES l to 3 To show the stabilizing effect of the association of trioxane, tertiary butanol and butylene oxide on trichloro-l ,l ,l ethane, the following test has been conducted:

40 ml trichloro-1,l,l ethane are placed in a reflux condenser along with the stabilizer in the form of an aluminum plate of 99.9 percent purity, 1 mm thick, mm long and 12 mm wide. This plate is partly immersed into the trichloro-l,l,l ethane. The heating time in the reflux condenser preceding the release of acid vapors and/or the buildup of a coloration of trichloro-l ,l ,1 ethane indicates the stabilization aptitude of the tested stabilizer combination.

The following table compiles the result obtained from the stabilization test of trichloro-l ,l ,1 ethane. For comparison and to better show the interest in this invention this table also shows the result of tests carried out individually with the following compounds: trioxane and tertiary butanol. A control test with trichloro- 1,1,1 ethane containing no stabilizer also is included in this table.

TABLE Contents of Grams of Time pre- Ex.

Stabilizer mixture of stabilizer ceding No. stabilizers or of mixappearance in by ture of staof acid weight bilizers per vapors or 100 grams coloration trichloro-l, in hours 1,1 ethane l trioxane 80 2.5 120 tertiary butanol 2O 2 trioxane 50 tertiary butanol S 3 120 3 trioxane 66 tertiary butanol 17 butylene oxide 16 3 I20 control 0 0.05 trioxane 0.5 0.25 1 l 2 40 3 48 with appearance of black point in vapor phase on Al tertiary butanol 0.5 4 l 48 55 wit coloration in yellow EXAMPLE 4 1.9 percent by weight of trioxane in combination with 0.25 percent by weight of butylene oxide, 1.] percent by weight of acetonitrile and 0.75 percent by weight of nitromethane were added to 100 cc (132.5 grams) of trichloro-1,1,l ethane. The resulting compound is placed in a reflux condenser in the presence of EXAMPLES 5 to 11 By way of further examples, compositions were prepared with 1,1,l-trichloroethane containing the components as set forth in the following table and the compositions were submitted to tests for stabilization as in Example 4.

Example 6 7 8 9 10 11 Trioxnne 1.5 1.0 2.0 1.0 1.0 1.0 1.0

Anal: 4;

Nitromethane Butylene oxide Acetonitrile Tertiary amyl alcohol Tertiary butyl alcohol This stabilization formula which associates with relatively high boiling point trioxane offers the advantage of making it possible to obtain during the course of redistillation of trichloro-l,1,l ethane a good distribution of the components of the stabilization formula.

It will be understood that changes may be made in the formulation and operation without departing from the spirit of the invention, especially as defined in the following claims.

Iclaim:

1 A method for stabilizing halogenated saturated aliphatic hydrocarbon solvents having from one to four carbon atoms comprising the steps of forming a combination consisting essentially of trioxane, associated with at least one member selected from the group consisting of a lower alcohol and a liquid epoxide and adding said combination to the hydrocarbon, wherein 0.001 to 15 percent by weight of trioxane is associated with from 0.1 to 7.5 percent by weight of the alcohol when present and 0.1 to 4 percent by weight of the liquid epoxide when present.

2. A method as claimed in claim 1 in which the halogenated hydrocarbon is selected from the group consisting of dichloroethanes, trichloroethanes, tetrachloroethanes, 1,2-dichloropropanes, 1,2-dichloro and 2,3-dichlorobutanes, tribromoethanes and 1,2- dibromopropane.

3. A method as claimed in claim 1 wherein the alcohol is tertiary butanol.

4. A method as claimed in claim 1 in which the epoxide is butylene oxide.

5. A method as claimed in claim 1 wherein at least one member comprising a C, to C alkyl nitrile and a C, to C, nitroalkane is also associated with the trioxane in an amount within the range of 0.1 to 4 percent by weight.

6. A method as claimed in claim 1 in which the halogenated solvent is trich1oro-1,1,1 ethane.

7. A method as claimed in claim 5 in which the alkyl nitrile is acetonitrile and the nitroalkane is nitromethane.

8. A method as claimed in claim 1 in which the boiling point of the compounds associated with trioxane does not differ by more than 50 C from the boiling point of the halogenated saturated aliphatic hydrocarbon.

9. A stabilized composition consisting essentially of a halogenated saturated aliphatic hydrocarbon having from one to four carbon atoms containing from 0.001 to 15 percent by weight of trioxane and at least one member comprising from 0.1 to 7.5 percent by weight of a lower alcohol and from 0.1 to 4 percent by weight of a liquid epoxide.

10. A composition as claimed in claim 9 containing in addition a compound selected from the group consisting of a C, to C, alkyl nitrile and a C, to C nitroalkane in which the compound is present in an amount within the range of 0.1 to 4 percent by weight.

11. A composition asclaimed in claim in which the alkyl nitrile is acetonitrile and the nitroalkane is nitromethane.

12. A stabilized composition consisting essentially of a halogenated saturated C to C aliphatic hydrocarbon solvent stabilized with trioxane present in an amount within the range of 0.001 to l5 percent by weight, at least one of the members selected from the group consisting of a lower alcohol and a liquid epoxide and mixtures thereof in which the alcohol is present in an amount within the range of 0.1 to 7.5 percent by weight when present, and the liquid epoxide is present in an amount within the range of 0.1 to 4 percent by weight when present, and at least one compound selected from the group consisting of a C to C alkyl nitrile'and a C 1,2-dichloropropanes, 1,2-dichloro and 2,3- dichlorobutanes, tribromoethanes and 1,2- dibromopropane.

M. A stabilized composition as claimed in claim 12 in which the compound is present in an amount within the range of 0.3 to 2 percent by weight. 

2. A method as claimed in claim 1 in which the halogenated hydrocarbon is selected from the group consisting of dichloroethanes, trichloroethanes, tetrachloroethanes, 1,2-dichloropropanes, 1,2-dichloro and 2,3-dichlorobutanes, tribromoethanes and 1,2-dibromopropane.
 3. A method as claimed in claim 1 wherein the alcohol is tertiary butanol.
 4. A method as claimed in claim 1 in which the epoxide is butylene oxide.
 5. A method as claimed in claim 1 wherein at least one member comprising a C1 to C4 alkyl nitrile and a C1 to C4 nitroalkane is also associated with the trioxane in an amount within the range of 0.1 to 4 percent by weight.
 6. A method as claimed in claim 1 in which the halogenated solvent is trichloro-1,1,1 ethane.
 7. A method as claimed in claim 5 in which the alkyl nitrile is acetonitrile and the nitroalkane is nitromethane.
 8. A method as claimed in claim 1 in which the boiling point of the compounds associated with trioxane does not differ by more than 50* C from the boiling point of the halogenated saturated aliphatic hydrocarbon.
 9. A stabilized composition consisting essentially of a halogenated saturated aliphatic hydrocarbon having from one to four carbon atoms containing from 0.001 to 15 percent by weight of trioxane and at least one member comprising from 0.1 to 7.5 percent by weight of a lower alcohol and from 0.1 to 4 percent by weight of a liquid epoxide.
 10. A composition as claimed in claim 9 containing in addition a compound selected from the group consisting of a C1 to C4 alkyl nitrile and a C1 to C4 nitroalkane in which the compound is present in an amount within the range of 0.1 to 4 percent by weight.
 11. A composition as claimed in claim 10 in which the alkyl nitrile is acetonitrile and the nitroalkane is nitromethane.
 12. A stabilized composition consisting essentially of a halogenated saturated C1 to C4 aliphatic hydrocarbon solvent stabilized with trioxane present in an amount within the range of 0.001 to 15 percent by weight, at least one of the members selected from the group consisting of a lower alcohol and a liquid epoxide and mixtures thereof in which the alcohol is present in an amount within the range of 0.1 to 7.5 percent by weight when present, and the liquid epoxide is present in an amount within the range of 0.1 to 4 percent by weight when present, and at least one compound selected from the group consisting of a C1 to C4 alkyl nitrile and a C1 to C4 nitroalkane in which the compound is present in an amount within the range of 0.1 to 4 percent by weight.
 13. A stabilized composition as claimed in claim 12 in which the halogenated saturated aliphatic hydrocarbon is selected from the group consisting of dichloroethanes, trichloroethanes, tetrachloroethanes, 1,2-dichloropropanes, 1,2-dichloro and 2,3-dichlorobutanes, tribromoethanes and 1,2-dibromopropane.
 14. A stabilized composition as claimed in claim 12 in which the compound is present in an amount within the range of 0.3 to 2 percent by weight. 